<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../Vue.js/vue.js"></script>
</head>
<body>
    <div class="root">
        <h2 :style = "{opacity}">欢迎学习Vue</h2>
    </div>
</body>
<script>

    /*const vm = */
    new Vue({
        el: ".root",
        data: {
            //只要改变属性值就会重新加载模板
            opacity: 1
        },
        methods: {},
        //Vue完成模板的解析并把真实DOM元素放入页面后(挂载完毕)调用mounted mount挂载
        mounted(){
            setInterval(() => {
                this.opacity -= 0.01
                if(this.opacity<=0) this.opacity = 1
            }, 10)
        }
    })

    //外部定时器
    /* setInterval(() => {
        vm.opacity -= 0.01
        if(vm.opacity===0) vm.opacity = 1
    }, 100) 
    */
</script>
</html>